RESUMO
A marine biological invasion is a natural process accelerated by human activities, and the crab Charybdis hellerii is an example of a globally widespread invasive species. This study evaluated color variation in C. hellerii and its relationship to the sex, size and sexual maturity of these crabs, and compared the efficiency of a freeware digital image-editing program with a commercially available program. The color of the individuals was analyzed using standardized digital images. The color pattern varied significantly with size; smaller and immature individuals were darker than larger and mature ones. The female abdomen changed in morphology and color with sexual maturity, becoming wider and orange-colored. There was no statistical difference in the color values between males and females and immature males did not show morphological or color differences in their abdomen. This study highlights the possible relationships of the color and physiological state of the reproductive system, which could help in future studies of behavior, avoiding the need to dissect and/or remove individuals from nature for assessment of sexual maturity. The freeware program showed the same efficiency in digital image analysis as a widely known commercial program.
Assuntos
Braquiúros/anatomia & histologia , Braquiúros/crescimento & desenvolvimento , Pigmentação , Maturidade Sexual , Animais , Braquiúros/classificação , Brasil , Cor , Feminino , Espécies Introduzidas , Masculino , Caracteres SexuaisRESUMO
The mangrove crab Ucides cordatus is one of the most exploited crustaceans in Brazil. The present study investigated the breeding season of this species and the period of the "andada" phenomenon, when the crabs are active outside their burrows and perform agonistic behaviors. Furthermore related them to environmental factors, in a mangrove on the coast of Brazil, with inferences about management of this crab. The crabs reproduced from October through February. The "andada" occurred from November through February, with typical characteristics in the first two months, during the full and new moon periods, and was influenced positively by the air and soil temperature, luminosity, and tidal amplitude, and negatively by salinity. Based on the results of the present study, the period when the "andada" occurs in other parts of Brazil could be defined, which will aid in managing this fishery. For Iguape, state of São Paulo, Brazil, we suggest a legal off-season for both sexes in December or during the full and new moon, including January.
Assuntos
Braquiúros/fisiologia , Animais , Braquiúros/classificação , Braquiúros/crescimento & desenvolvimento , Brasil , Conservação dos Recursos Naturais , Monitoramento Ambiental , Feminino , Pesqueiros , Masculino , Reprodução/fisiologia , Estações do AnoRESUMO
Trawl fisheries are associated with catches of swimming crabs, which are an important economic resource for commercial as well for small-scale fisheries. This study evaluated the population biology and distribution of the swimming crab Callinectes ornatus (Ordway, 1863) in the Estuary-Bay of São Vicente, state of São Paulo, Brazil. Crabs were collected from a shrimp fishing boat equipped with a semi-balloon otter-trawl net, on eight transects (four in the estuary and four in the bay) from March 2007 through February 2008. Specimens caught were identified, sexed and measured. Samples of bottom water were collected and the temperature and salinity measured. A total of 618 crabs were captured (332 males, 267 females and 19 ovigerous females), with a sex ratio close to 1:1. A large number of juveniles were captured (77.67%). Crab spatial distributions were positively correlated with salinity (Rs = 0.73, p = 0.0395) and temperature (Rs = 0.71, p = 0.0092). Two peaks of recruitment occurred, in summer and autumn, and ovigerous females were mostly captured during summer, showing a seasonal reproductive pattern. The results showed that C. ornatus uses the bay as a nursery area for juvenile development. Callinectes ornatus is not yet a legally protected species, and the minimum allowed size of crabs caught in the area, although already restricted, should be carefully evaluated since the removal of large numbers of juveniles could negatively impact the local population.
Assuntos
Animais , Braquiúros/classificação , Braquiúros/fisiologia , Distribuição Animal , Estuários , Migração Animal , BrasilRESUMO
Trawl fisheries are associated with catches of swimming crabs, which are an important economic resource for commercial as well for small-scale fisheries. This study evaluated the population biology and distribution of the swimming crab Callinectes ornatus (Ordway, 1863) in the Estuary-Bay of São Vicente, state of São Paulo, Brazil. Crabs were collected from a shrimp fishing boat equipped with a semi-balloon otter-trawl net, on eight transects (four in the estuary and four in the bay) from March 2007 through February 2008. Specimens caught were identified, sexed and measured. Samples of bottom water were collected and the temperature and salinity measured. A total of 618 crabs were captured (332 males, 267 females and 19 ovigerous females), with a sex ratio close to 1:1. A large number of juveniles were captured (77.67%). Crab spatial distributions were positively correlated with salinity (Rs = 0.73, p = 0.0395) and temperature (Rs = 0.71, p = 0.0092). Two peaks of recruitment occurred, in summer and autumn, and ovigerous females were mostly captured during summer, showing a seasonal reproductive pattern. The results showed that C. ornatus uses the bay as a nursery area for juvenile development. Callinectes ornatus is not yet a legally protected species, and the minimum allowed size of crabs caught in the area, although already restricted, should be carefully evaluated since the removal of large numbers of juveniles could negatively impact the local population.(AU)